Ellipsograph



Feb. 28, 1950 o, P, EDWARDS 2,498,798

ELLIPSOGRAPH Filed Dec. 31, 1946 INVENTOR.

Patented Feb. 28, 1950 UNI-TED STATES 2',49s,79s:- r i Y ELLIPSOGR'A'PH" OsborneP. Edwards, Maywood, .N-.. J.- I Application fiecember 31, 1946, SerialIN'o. 719,413"

presentinventionrelates to an improved ellipsograph and'm'o'r'e particularly to a compass having a fixed standard and a radially movable scriber, together with means for moving the scriber as the frame therefor is rotated whereby a closed curved figure such as an oval may be scribed.

In the accompanying drawings I have illustrated one complete example of the physical embodiment of my invention according to the best mode I have thus far devised, but it will be understood that various changes and alterations may be made in the exemplified structure within the scope of the appended claims.

In the drawings:

Fig. 1 is a perspective view of the ellipsograph of my invention.

Fig. 2 is a detail view of the standard base.

Fig. 3 is a detail view of the scriber device.

Fig. 4 is a perspective view of the bearing for the opening center disk.

Fig. 5 is a perspective view of the adjustment control for the scriber.

Referring now to the drawings, I have illustrated as the present preferred embodiment of my invention the structure comprising a standard 2 having a base 4 formed with spaced pins 6 and an interior central post 8, vertically movable and pressed downwardly by spring 9. Openings A permit sighting the post 8 for the proper positioning thereof. An open center disk H1 is horizontally pivotally secured by friction to a collar l2 which is adjustably mounted on the standard and fixed relative thereto by screw [4. A parallel arm it is pivotally mounted on the standard by links 18 secured by screw 20 to collar 22 and links 24 secured on shafts 26 extending through the hub 21 journaled on the standard. A bearing 28 is mounted on the arm It for surface contact with the periphery of the disk It as the arm I and links are rotated by the knurled cap 30. A spring 32 has coils 45 about the shafts 26 and the frame arms 35. The tension of the coils 45 tend to force the frame arms 36 toward the standard 2. The frame arms 36 are journaled on the ends of the shafts 26. A look comprising the sections 38-40 is secured on the frame arms by knurled nut 42 and the section 49 rests on theedge 44 of the arm IS. The coils 45 urging the frame arms 35 toward the standard 2 causes the lock to be retained in constant engagement with the edge 44 of the arm 16.

On the ends of the frame arms I provide a link 46 to which is secured the joint 48 having screw 50 to secure the curved arm 52 of the tubular im- 2 Claims. (Cl.'33-30 ple'mena carrying post 54? A telescoping rod' 56 ext'ends 'from' the post and maybecl'amped inth'e splitend's 58 and 60 ofthe post 54* by levers-6'2 having an eccentric link 63 and is capped by ball 64. The line writing element is here shown as a tube 66 for the lead point 68 which is adjustable by a cap nut 10. The lead point 68 may have substituted therefor an ink ruling pen l2 formed with three adjustable points 14 the usual two point pen not being satisfactory for the purpose designed. Both the tube 66 and pen 12 have a threaded rod 18 having a head 16 thereon provided with a pin 1'! for adjustment of the tube 66 and pen 12, both of which are adapted to be inserted into the post 54 as shown in dotted lines Fig. 1. A slot inside rod 56 engages the pin 'l'! and by rotating nut It the plunger 3| on the lower end of the rod 18 will engage the upper end of the lead 68 whereby the lead will be lengthened. The gap between the points 14 of the pen will be adjusted as the plunger 8| is moved up or down within the points by means of the nut 10' on the rod 18, Fig. 3. The tube 66 and pen 12 are provided with longitudinal slots 82. The slotted construction providing frictional engagement of the tube and pen in the post 54.

A needle secured at 82 in the base 4 may be used to center the oval over a straight line.

In operation a center mark is determined and a straight line is drawn through. the center mark in the direction of the long axis of the oval. The writing implement within the post 54 is vertically adjusted to clear the writing surface when the base 4 is positioned with the pin 8 centered. The needle 89 is aligned with the longitudinal axis and the base is pressed down to engage the pins 5. The needle is removed and by means of lock 3840 the instrument is set for the long axis of the oval which is always in alinement with the needle 80. Then the position of the disc is moved to adjust the instrument to the shape of the oval, while the lock is moved to adjust the instrument to the size of the oval. Then after releasing the clamp 6'2 and by rotating the cap 3E! the compass revolves about the fixed standard and an oval will be inscribed.

Having thus fully described my invention what I claim as new and desire to secure by Letters Patent is:

1. In an ellipsograph embodying a fixed standard having an open center disk provided with a diametrical pivot extending diametrically through the standard so that the disk inv position other than a plane perpendicular to the standard will present a projected form other than a circle, the improvement comprising, a hub journalled on the standard at the upper end thereof, a collar journalled on the standard intermediate of said disk and said arm, links pivotally connected to said hub, second links pivotally connected to said collar, an arm pivotally connected to said links at its opposite ends so that said arm is in parallel relation to said standard with the lower end of the arm bearing against the perimeter of the disk, shafts extending outwardly of and at right angles to said hub in opposite directions therefrom, frame arms journalled on the ends of said shafts, lock means adjustable along the frame arms and adapted to have sliding engagement with said arm, a Writing implement carried by the ends of said frame arms, and said frame arms being movable radially of the standard upon rotation of said writing implement around the standard for the inscribing of an oval.

2. The improvements as in claim 1 wherein a tension spring is mounted on said hub and said shafts to tension said frame arms so that said lock means is maintained in constant engagement with said arm, and the adjustment of the lock means with relation'to said arm will expand or contract the dimensions of the ellipse being drawn.

OSBORNE P. EDWARDS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,290,812 Wayditch Jan. 7, 1919 FOREIGN PATENTS Number Country Date 196,682 Germany Mar. 23, 1908 603,712 Germany Oct. 6, 1934 OTHER REFERENCES Davies, Elliptograph, Journal of Franklin Institute, vol. 34, page 85, August 1842. 

